In a bold bid to seize a House seat that has long been considered comfortably in the Democratic column, the National Republican Congressional Committee late last week reserved $206,000 of TV time in California’s 20th district, where Rep. Cal Dooley (D) is retiring.

The NRCC buy comes as the Republican nominee in the Central Valley seat, state Sen. Roy Ashburn, was expected to reap a huge windfall from a fundraiser Monday night with popular Golden State Gov. Arnold Schwarzenegger (R).

“We think Roy Ashburn is a great candidate,” said NRCC spokeswoman Caryn McLeod. “Schwarzenegger is not really out there campaigning for a lot of people. So we think that’s an indicator of how well he’s doing.”

But Democrats remain confident that in a district that preferred Al Gore to George W. Bush by 11 points in 2000, their candidate, former state Sen. Jim Costa, is in solid shape.

“This is a 67-percent Democratic district, and we have a strong candidate who overwhelmingly won his primary and is a proven vote-getter in the district,” said Greg Speed, a spokesman for the Democratic Congressional Campaign Committee.

No independent polling has been released in the race to date. Still, the NRCC buy suggests that the results of the Ashburn-Costa race — the only one of California’s 53 House contests that is even remotely competitive this cycle — may not be a foregone conclusion.

Although the heavily agricultural district that stretches from Fresno and Bakersfield generally favors Democrats, many of the voters are conservative, particularly on social issues. And, as Republicans are fond of pointing out, the 20th district voted overwhelmingly for the recall of ex-California Gov. Gray Davis (D) last year and for Schwarzenegger in the simultaneous election to replace Davis.

Davis is a central character in the ad the NRCC began running in the district Monday.

Ashburn has sought to paint Costa, who represented most of the Central Valley at one time or another during two dozen years in the state Legislature, as too liberal for the district. After Costa recently appeared at an event with Oakland Mayor and former California Gov. Jerry Brown (D), Ashburn issued a news release accusing Costa of turning over his campaign to liberals in San Francisco and Washington, D.C.

“It’s clear Mr. Costa’s campaigns, once run by San Francisco’s Willie Brown, is now being run by Nancy Pelosi’s operatives from Washington, D.C.,” the release said in part.

Both camps have been aggressively raising money. As of June 30, Ashburn had $376,000 in the bank. Costa, who spent about $850,000 to win his March Democratic primary contest with former Dooley chief of staff Lisa Quigley, had $279,000.

Tracy Leach, a spokeswoman for Ashburn, said that there were no firm figures yet on the take from Monday’s fundraiser at the Fresno Convention Center. Ashburn collected $250,000 at a fundraiser with Vice President Cheney in July. Two other GOP celebrities are scheduled to stump for Ashburn in the next two weeks: Interior Secretary Gale Norton and Agriculture Secretary Ann Veneman, a farmer who lives in the Central Valley.

“We’re feeling a lot of momentum,” Leach said.

The NRCC’s $200,000 allocation will buy a substantial amount of TV time in the district’s two relatively inexpensive media markets in the next two weeks. But just what kind of ads the committee puts up could have a major bearing on the tone of the campaign’s final six weeks, if not the ultimate outcome.

Republican officials have repeatedly referred to Costa as a “flawed candidate” — a none too subtle reference to the fact that he was arrested for soliciting a prostitute in the 1980s and that police discovered drug paraphernalia in his home in 1994. But when Quigley, Costa’s primary opponent, ran ads reminding voters of these embarrassing facts, her standing fell precipitously — and the Fresno Bee rescinded its endorsement of her. Costa wound up winning what had once been assumed to be a close primary, 71 percent to 29 percent.

Still, Democrats are apparently girding for a GOP attack. Coincidentally but fortuitously for the Democrat, Costa last week was endorsed by the California Narcotics Officers Association.

And in an effort to at least take some of the luster off Ashburn’s Schwarzenegger event, the Costa campaign on Monday held a news conference to spotlight 230 prominent Republicans who are supporting the Democrat. The list includes Pete Mehas, Fresno County Superintendent of Schools; Susan Anderson, Fresno County supervisor; Tony Olivera, Kings County supervisor; retired Fresno County Sheriff Steve Magarian; and Fresno business leaders Gary Bruno and Mike Patton.

Bob Sanders, a spokesman for Costa, said that about one-third of the $1.2 million Costa has raised for the race has come from Republican individuals or GOP-leaning interest groups. Costa also resumes his TV advertising this week.

Despite the fact that he appears to be exceeding initial expectations, the campaign hasn’t been all smooth sailing for Ashburn. At an anti-gay marriage rally in Fresno last month, Ashburn criticized Costa’s support of domestic partnerships in Sacramento. Prompted by Ashburn’s remarks, the crowd of 2,000 booed Costa’s name.

But then, according to the Fresno Bee, Fresno Mayor Alan Autry, who organized the rally, called Ashburn’s attempts to use the event for partisan attacks “inexcusable.” Ashburn later apologized.

Many political observers have expected the national GOP to spend freely on Ashburn’s campaign all along, the theory being that the NRCC would have far more discretionary money than the DCCC would during the final weeks of the cycle.

But Speed argued that the Republicans’ attempts to prop up Ashburn is more a sign of their recruiting failures in more competitive districts than an attempt to use surplus funds to artificially create a close race.

“This confirms that the Republicans are so desperate for districts they can play in that they’re looking to play in this overwhelmingly Democratic district,” he said.